Mitsubishi QJ71C24/-R2 User Manual page 255

10 TROUBLESHOOTING
Status
No. signal
name
1 SD WAIT Transmission wait status
2 SIO SIO error status
Communication protocol
3 PRO.
error status
Status of parity error or
4 P/S
sum check error
Access status with the
5 C/N
PLC CPU
Abnormal completion
6 NAK
status
Normal completion
7 ACK.
status
Neutral status
8 NEU. Waiting to receive
command
Error occurrence status
9 CH2. ERR
on CH2 side
Error occurrence status
10 CH1. ERR
on CH1 side
10 - 4
(3) Checking by GX Configurator-SC
Display the "Monitor/test others" screen.
For details on display screens, see Section 8.6.9 of the User's Manual (Basic).
(4) Description of LED ON status and communications error status
Description when ON
Description (when LED is turned on
Waiting for data
transmission
Overrun or framing
error occurred.
OS area is full.
Received data was
deleted.
Error occurred.
Error occurred.
( )
1
Abnormal completion
transmission
Normal completion
transmission
Neutral
Switch setting error
Mode switching error
Transmission error
Reception error
On-demand error
1 C/N turns on in the following cases:
• An external device issued a data read request to the PLC CPU when write
during RUN is set to prohibit in the switch settings by GX Developer (see
Section 4.5.2).
For functions that cannot be used when write during RUN is set to prohibit, see
the explanation section in each command list of the Reference Manual.
• When an error has occurred during access between the Q series C24 and the
PLC CPU.
2 NEU. is valid when a target interface is set to use the MC protocol.
When the target interface is set to other than the MC protocol, the status of NEU.
is off.
Description when OFF
(when LED is turned off
(1)) (0))
Data transmission start
Normal
Normal
Normal
Normal
Normal completion
transmission
Abnormal completion
transmission
Command reception
Normal
MELSEC-Q
Related protocol
Initial Non
state
MC procedure
protocol
OFF
OFF
OFF —
OFF
OFF
OFF
OFF
OFF
( )
2
OFF
OFF
Bidirection-
al protocol
—
—
10 - 4